1. Field
The described technology relates generally to a rechargeable battery and a battery module. More particularly, the described technology relates generally to a rechargeable battery and a battery module having a case with an improved structure.
2. Description of the Related Technology
A rechargeable battery can be recharged and discharged, in contrast to a primary battery that cannot be recharged. A low capacity rechargeable battery is generally used as a power source for a small portable electronic device, such as a mobile phone, a laptop computer, and a camcorder, etc., and a large capacity rechargeable battery is generally used as a power source for driving a motor such as for a hybrid vehicle.
A large capacity high power rechargeable battery with high energy density using a non-aqueous electrolyte has been developed, and the rechargeable battery is generally formed with a large capacity high power rechargeable battery module by coupling a plurality of rechargeable batteries in series or in parallel in order to use it to drive a device, for example, a motor such as an electric vehicle requiring a large amount of electric power.
Further, a high power rechargeable battery is generally formed with a plurality of rechargeable batteries that are coupled in series or in parallel, and the rechargeable battery may be formed in a cylindrical shape or a square shape.
A conventional rechargeable battery includes an electrode group in which a positive electrode and a negative electrode are positioned with a separator interposed therebetween, a metal can having a space that houses the electrode group, a cap plate that closes and seals the metal can and in which a terminal hole that has a terminal inserted therein is formed, and a terminal that is electrically connected to the electrode group and that is inserted into the terminal hole to protrude to the outside of a case.
A lithium ion battery among existing rechargeable batteries is used as a small mobile terminal battery, uses a small metal can or a film type pouch sheath material, and has a secure sealing structure through welding or fusing in order to isolate the outside from the inside of the battery.
However, a pouch type battery is weak with respect to external impact and cannot easily discharge heat. Further, because the pouch type battery has no structure that fixes its external shape, it is difficult to manufacture the pouch type batteries with a battery module by stacking.
A metal can type battery has high strength, but has a heavy weight and has a difficulty in discharging internal heat to the outside.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.